Lyrical
Check out this passage from Omeros, in which the narrator describes his experience with the foam bust of Homer at Antigone's house:
But if I could read between the lines of her floor
like a white-hot deck uncaulked by Antillean heat,
to the shadows in its hold, its nostrils might flare
at the stench from manacled ankles, the coffled feet
scraping like leaves, and perhaps the inculpable marble
would have turned its white seeds away, to widen
the bow of its mouth at the horror under the table (II.ii.15)
This use of lyric verse focuses on the emotional inner life of the characters or the narrator. Here we get a flash of the intense ancestral suffering the narrator keeps just under the surface and imagine the response of the most revered poet in the ancient world. Walcott excels at accessing the inner lives of his characters and uses his verse form to advantage when describing it.
But Walcott's verse is lyrical in a more general sense, too. He's able to capture the musical nature of language—both standard English and the dialect of St. Lucia—in the swing and rhythm of each line. Here's a great example of this:
"Touchez-i, encore: N'ai fender choux-ous-u, salope!""Touch it again, and I'll split your arse, you b****!" "Moi j'a dire—'ous pas prêter un rien. 'Ous ni shallope,
'ous ni seine, 'ous croire 'ous ni choueur campêche?" (III.i.15-16)
Even if you can't read/speak French, you can see how the end-rhymes work and feel the rhythm of the lines. That's because Walcott writes loosely in hexameters (the meter of choice for Homer—shocking, we know), using full and near-rhymes to create the sense that this poem should be read aloud (or sung). Just like its predecessors.